Abstract
BACKGROUND: Porcine epidemic diarrhea virus (PEDV) is a highly virulent enterovirus that is responsible for severe diarrhea in neonatal piglets. For no effective vaccine or specific treatment are available, rapid and accurate diagnosis is crucial for the prevention and control of disease. The nucleocapsid (N) protein is conserved with strong immunogenicity, making it an important target for developing serological approaches. RESULTS: In this study, soluble PEDV N protein was expressed, purified, and then used to produce monoclonal antibodies (mAbs). Three mAbs, named 8G2, 6F3, and 3E1, against PEDV N protein were generated. These mAbs were identified as IgG1 isotypes with κ light chains, exhibited high specificity for PEDV, and showed no cross-reactivity with transmissible gastroenteritis virus (TGEV) or porcine deltacoronavirus (PDCoV). Epitope mapping revealed 8G2 specifically recognized a novel linear B-cell epitope at 274-DLKDIPEWR-282 of viral N protein by using a serious of truncated overlapping peptides. Homology analysis showed that the epitope of 8G2 was highly conserved (100%) among different PEDV strains. Structural assay suggested that the identified epitope was located on the surface of PEDV N protein. Functional analysis demonstrated 8G2 could be used in indirect immunofluorescence assay, western blot, flow cytometry, and immunohistochemistry. CONCLUSIONS: These mAbs help us better understanding the antigenicity of PEDV N protein, and serve as robust tools for serological diagnosis and vaccine development.